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<title>Data preparation : Transform</title>

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  <p><b>PREPARATION</b></p>

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<p>Sometimes, DataSets in KEEL format cannot be used in experiments, because bring 

  some errors. Probably, these errors are due to a problem with the algorithm 

  connected to the DataSet. The algorithm is not prepared for a &quot;special feature&quot; 

  present in the DataSet, like null values, nominal attributes, etc. </p>

<p>To solve this problem, in this section, users can find a lot of tools or utilities, 

  that modify the content of a DataSet and generate a new file. This new file 

  can be used in experiments like others.</p>

<p>To apply a transformation is very simple, since there are necessary only three steps:</p>

<ol>

  <li>Select an existing DataSet.</li>

  <li>Select the name of the transformed DataSet.<br><br>
<div align="center"><img src="imag/data_preparation.jpg"></div></li>

  <li>Select the transformation to apply.</li>

</ol>

<p>Transformation have been classificated in three types:</p>

<ul>

  <li><b>Instance selection</b>: contains some algorithms that can reduce a DataSet 

    deleting instances from it.</li>

  <li><b>Feature selection</b>: contains algorithms that can reduce the number of attributes 

    of the DataSet.</li>

  <li><b>Other</b>: various useful transformations like ranging, null values deleting, 

    etc.</li>

</ul>

<p align="center"><img src="imag/data_trans1.jpg"></p>

<p>Also it is possible to modify the transformation parameters (only if the algorithm 

  allow it); just press the &quot;Parameters&quot; button, and a new dialog containing the list of parameters 

  will be opened. This 

  dialog seems like this:</p>

<p align="center"><img src="imag/data_trans2.jpg"></p>

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